FIRST VLA survey: The automated analysis pipeline. [VLA (very large array)]

In April 1993, the first 2200 fields of the FIRST (Faint Images of the Radio at Twenty-cm) VLA survey were observed, covering a narrow strip 2.5[degrees] by through the North Galactic Pole (NGP). This survey will eventually cover square degrees around the NGP with 60,00 fields. The data are taken B-configuration of the VLA and have a 180 s integration time per field. in a resolution of 5 inches FWHM and a sensitivity of 1 mJy (6.5[sigma]). The authors have built and tested an automated pipeline which edits, self-calibrates, the data. By taking advantage of the existing single-dish 20 cm catalog derived from the Greenbank Sky Survey (White and Becker) to reduce the required dirty map size used in the initial self-calibration we have achieved a processing time per 2048 x 2048 image of 90 minutes SPARC-10/41 processor. The authors map bright sources lying in sidelobes of the primary beam without the need for any manual intervention or iteration mapping process. With the exception of the small number ([approximately] 5%) of containing sources brighter than [approximately]150 mJy, the resulting images achieve theoretical sensitivity limit of 0.15 mJy rms at the field center. In addition, the authors demonstrate an absolute positionalmore » accuracy better than 0.3 inches over the entire field of view (50[prime]).« less